Print Email Facebook Twitter Sulfide induced phosphate release from iron phosphates and its potential for phosphate recovery Title Sulfide induced phosphate release from iron phosphates and its potential for phosphate recovery Author Wilfert, P.K. (TU Delft BT/Environmental Biotechnology; Wetsus, Centre for Sustainable Water Technology) Meerdink, J. (Wetsus, Centre for Sustainable Water Technology) Degaga, B. (Wetsus, Centre for Sustainable Water Technology) Temmink, H. (Wageningen University & Research) Korving, L. (Wetsus, Centre for Sustainable Water Technology) Witkamp, G.J. (TU Delft BT/Environmental Biotechnology; King Abdullah University of Science and Technology) Goubitz, K. (TU Delft RST/Technici Pool) van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology) Date 2020 Abstract Sulfide is frequently suggested as a tool to release and recover phosphate from iron phosphate rich waste streams, such as sewage sludge, although systematic studies on mechanisms and efficiencies are missing. Batch experiments were conducted with different synthetic iron phosphates (purchased Fe(III)P, Fe(III)P synthesized in the lab and vivianite, Fe(II)3(PO4)2*8H2O), various sewage sludges (with different molar Fe:P ratios) and sewage sludge ash. When sulfide was added to synthetic iron phosphates (molar Fe:S = 1), phosphate release was completed within 1 h with a maximum release of 92% (vivianite), 60% (purchased Fe(III)P) and 76% (synthesized Fe(III)P). In the latter experiment, rebinding of phosphate to Fe(II) decreased net phosphate release to 56%. Prior to the re-precipitation, phosphate release was very efficient (P released/S input) because it was driven by Fe(III) reduction and not by, more sulfide demanding, FeSx formation. This was confirmed in low dose sulfide experiments without significant FeSx formation. Phosphate release from vivianite was very efficient because sulfide reacts directly (1:1) with Fe(II) to form FeSx, without Fe(III) reduction. At the same time vivianite-Fe(II) is as efficient as Fe(III) in binding phosphate. From digested sewage sludge, sulfide dissolved maximally 30% of all phosphate, from the sludge with the highest iron content which was not as high as suggested in earlier studies. Sludge dewaterability (capillary suction test, 0.13 ± 0.015 g2(s2m4)−1) dropped significantly after sulfide addition (0.06 ± 0.004 g2(s2m4)−1). Insignificant net phosphate release (1.5%) was observed from sewage sludge ash. Overall, sulfide can be a useful tool to release and recover phosphate bound to iron from sewage sludge. Drawbacks -deterioration of the dewaterability and a net phosphate release that is lower than expected-need to be investigated. Subject IronPhosphate recoverySewage sludgeSulfide To reference this document use: http://resolver.tudelft.nl/uuid:ce4ac086-db64-4539-89cd-18934af461db DOI https://doi.org/10.1016/j.watres.2019.115389 ISSN 0043-1354 Source Water Research, 171 Part of collection Institutional Repository Document type journal article Rights © 2020 P.K. Wilfert, J. Meerdink, B. Degaga, H. Temmink, L. Korving, G.J. Witkamp, K. Goubitz, Mark C.M. van Loosdrecht Files PDF 1_s2.0_S0043135419311637_main.pdf 639.25 KB Close viewer /islandora/object/uuid:ce4ac086-db64-4539-89cd-18934af461db/datastream/OBJ/view